1. Field of the Invention
The present invention relates generally to a damping force generating device for an oil damper used as a rear cushion in two-wheeled motor vehicles or the like. More particularly, the invention relates to a damping force generating device for an oil damper provided with a sub-tank having a gas chamber which is separate from a cylinder in which a piston is slidably inserted.
2. Description of Relevant Art
There has been known an oil damper of the type having a single cylinder provided with a sub-tank in which a volumetric change in the interior of the cylinder caused by a sliding motion of a piston therein, i.e., a volumetric change therein corresponding to an intruding or retreating volume of a piston rod, is compensated by a volumetric change of gas in the sub-tank, by hydraulically connecting the cylinder with the sub-tank.
Recently, in two-wheeled motor vehicles or the like, there has been a tendency to adopt a single rear cushion and mount it under a seat positioned centrally of the vehicle body, or thereabout. However, if the foregoing oil damper provided with a sub-tank is used for a rear cushion of this type, the structure of the damper, particularly the sub-tank, becomes complicated and large in size, and it is difficult to selectively change the damping characteristic of the damper. Thus, use of such an oil damper has not always been desirable from the standpoint of maintenance.
The present invention effectively overcomes the foregoing problems attendant the conventional oil damper.